Acellus slope intercept

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?

See attachment below and find the equivalent of tan(∠qsr)